1. Field of the Invention
This invention relates to improvements in fiber board products formed, through a number of special processes, from consolidated comminuted lignocellulosic materials and, more particularly, to a variety of fiber board products of improved physical characteristics formed by pressure treated comminuted lignocellulosic woody materials, adhesive binders and ultrasonic sound. Furthermore, the present invention relates to fiber board compositions comprising pressure treated comminuted lignocellulosic woody material, adhesive binder and specified chemicals to yield, upon consolidation, a variety of structural building products of improved physical characteristics (high strength, fire resistance, water resistance, insect and rot resistance).
At present, boards made from wood and other lignocellulosic particles and the conventionally used thermosetting binder for consolidation of the particles have been shaped into panels or other shapes for limited applications. Often times, such fiber board products have included therein a particular combination of particulate filament material which is added for the purpose of improving desired characteristics of the finished fiber board product. For example, certain fibrous materials have been incorporated in the fiber board product in a specific orientation or fiber board products have been formed by distinct lamina, each lamina including a desired orientation of the added fibrous component. Obviously, such fiber board products can only be manufactured by relatively expensive processes in which specialized equipment is required in order to orient the fiber additions in the proper direction. Accordingly, while such fiber board products may have the desired physical characteristics, the expense of such products becomes prohibitive and use thereof extremely limited.
Similarly, there are no presently avilable structural fiber board products, in particular those made from comminuted lignocellulosic particles, which have sufficiently high strength, fire resistance, water resistance, and insect and rot resistance and are of a cost that allows such products to be readily utilized in home construction such as for walls and roof, ceilings and floors. Without forming fiber board products by time-consuming, energy-inefficient and expensive processes, the art has not provided a relatively inexpensive natural lumber substitute having the equivalent or much improved physical properties of natural lumber products, especially fiber board products which can be used readily as structural elements in building construction.
2. Disclosure Statement
U.S. Pat. No. 4,127,636, issued Nov. 28, 1978, to Flanders, discloses a process for making a reinforced board from lignocellulosic particles in which comminuted lignocellulosic particles, binders and other additives and additionally a plurality of elongate reinforcing filaments comprising a plurality of short filaments such as glass fibers or steel wires are distributed uniformly throughout the particle and binder mixture in a random orientation so as to extend generally in all directions. For board applications having greater flexural strength and stiffness requirements, the reinforcing filaments comprise a series of long filaments specifically oriented straightly in a predetermined direction corresponding to the direction of expected tensile strength and in a parallel arrangement spaced transversely from one another. The lignocellulosic particles which can be utilized are preferably woody particles such as sawdust, bark, etc., but the resultant product can also employ any fibrous lignocellulosic material including various grain and vegetable products such as corn stocks, either alone or in mixture with one or more of the other types of lignocellulosic materials. Additionally, the patent discloses that the ideal ratio of binder to lignocellulosic particles is between about two and six parts of binder to ten parts of particles by weight.
U.S. Pat. No. 3,916,059, issued Oct. 28, 1975, to Molloy et al, discloses crossbanding sheets which are made of a combination of glass fibers and cellulose fibers held together by a synthetic resin binder extending throughout the sheet, the fibers of the crossbanding sheets oriented in a direction perpendicular to the direction of orientation of wood chips or grain of a wood core to which the crossbanding sheets are adhered. The sheets comprise a combination of glass fibers and cellulose fibers in which the glass fibers are present in amounts of 5 to 85% by weight of the total fibers with the cellulosic fibers present in an amount of 95 to 15% of the total fibers. It was found that sheets made with 50 to 75% glass fibers and 50 to 25% cellulose fibers have been found to be particularly satisfactory. The binder which is preferably a thermosetting one can constitute about 20 to 60% of the weight of the final sheets.
U.S. Pat. No. 3,880,975, issued Apr. 29, 1975, to Lundmark, discloses a thin, continuous web produced from a starting material containing at least a major part of defibrated lignocellulose plant substances and a mixture of resinous binding agents amounting to at most 10% of the weight of the final product by first causing the starting materials to form a continuous porously felted fiber mat and subsequently feeding the fiber mat between a pair of cooperating nip-forming press rollers which are heated to a minimum temperature of 160.degree. C., the continuous web thus produced may be subjected to further treatment in order to obtain the required properties. In addition to lignocellulose fibers and resin binders, the starting material may include up to one-third of other kinds of fibers such as mineral fibers including asbestos, glass and rockwool fibers; animal textile fibers, vegetable textile fibers. It is further recommended to impregnate the fibers included in the starting materials with small amounts of moisture repellants, fire retarders, fungicides, insect repellants, etc.
U.S. Pat. No. 4,110,397, issued Aug. 29, 1978, to Wooler, discloses an improvement in the molding process for composite bodies of sheets, especially those from lignocellulosic material in which an isocyanate binding agent is used, the improvement being the provision of a metallic soap at the interface of the composition and mold surface to assist release. This patent defines lignocellulosic material as wood chips, wood fibers, and the like and/or fibers from other natural products which are lignocellulosic, for example, straw, dried rushes, reeds and grasses and may further include ground nuts and hulls from cereal crops. Additionally, there may be mixed with the lignocellulosic materials inorganic flake or fibrous material, for example, glass fiber, mica and asbestos.